My invention generally relates to a manually operated material handling vehicle commonly used on construction sites referred to as a wheel barrow.
The common wheel barrow generally consists of a material containing bucket mounted upon an A frame structure comprising two diverging longerons serving to support the bucket and provide handles by which the vehicle is operated A single wheel is mounted in the general vicinity of the A frame apex to provide mobility. Although simple in design the common wheel barrow requires much skill and dexterity to operate. For example, if the center of gravity of the load placed within the bucket is not directly on the longitudinal center line of the vehicle, which is generally the situation, a lateral rolling moment about the wheel-ground contact point is present. Thus when the operator grasps the handles and lifts the end of the vehicle, the vehicle exhibits lateral instability, or roll, about the longitudinal axis.
To stabilize the vehicle the operator must exert unequal forces on the handles. The amount of lifting force necessary to stabilize the vehicle is unknown until the operator first lifts the handles; trial and error then becomes necessary to stabilize the vehicle. During forward movement of the vehicle over an uneven surface the forces transmitted to the single wheel constantly vary thereby requiring constant adjustment, by the operator, of the unequal lifting forces applied to the handles. Because of the off center, center of gravity the stability of the vehicle is further complicated by the necessity of applying unequal forward thrust forces to the handles to propel the vehicle forward. Thus in operation of the single wheel, wheel barrow the operator must constantly vary the lift and thrust forces to each of the two handles. It is not uncommon to have a novice wheel barrow operator having a wheel barrow heavily loaded, with a greatly off center, center of gravity, operating over a rough surface to inadvertently dump the load.